Mold dumping



JunelO, 1969 o. v. MURPHY 3,448,873

- MOLD DUMPING Filed Dec. 18, 196? Sheet of z INVENTOR. @5648 U. MVP/ H)June 10, 1969 o. v. MURPHY MOLD DUMPING Sheet Filed Dec. 18, 1967INVENTOR.

45642 M Mue A F BY W June 10, 1969 o. v. MURPHY 3, 8,

MOLD DUMPING v I v Filed Dec. 18, 1967 Sheet Y J or 5 IN VEN TOR. as MMyer/a B Mg.

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United States Patent US. Cl. 214-4622 Claims ABSTRACT OF THE DISCLOSUREThis disclosure relates to a special mold dumping assembly enabling acombination of low profile, simplified construction with a dumpingplatform that tilts at its end. A mold car is moved from a stationaryfeeding track to the platform which is rotated upwardly to dump the loadfrom the car. After the car has been dumped, the platform rotates aboutthe axis downwardly to deliver the empty car to a stationary returntrack which is positioned beneath the feeding track, and the platformthen returns to its original position.

The platform or dumping track is moved between positions by a speciallyarranged and cooperative fluid pressure assembly comprising a pair ofcylinders attached directly to each other and positioned in side by sidebut oppositely oriented relationship. One cylinder has its piston rodattached to the platform at a point spaced from the pivot point, whilethe second cylinder has its piston rod attached to a fixed pivot mount.Controlled separate and cooperative actuation of the cylinders shiftsthe platform from the original position to the dumping position, fromthe dumping position to the car return position, and from the car returnposition back to the original position.

This invention relates to the dumping of molds positioned on wheeledvehicles. In one of its aspects it relates to a mold dumping assemblywherein a rotatable platform is rotated from a substantially horizontalfirst position about an angle in a first direction to a dumpingposition, about an angle in a second direction to a discharge positionand back to the original first position by a fluid pressure meanscomprising a first fluid cylinder with an extendible piston rod attachedto the platform at a point spaced from the axis of rotation, and asecond fluid cylinder attached to the first cylinder having anextendible piston rod attached to a fixed pivot point. 1

In another of its aspects the invention relates to a mold dumpingassembly as has been hereinbefore described wherein the first and secondcylinders are in side by side relationship.

A variety of mold dump mechanisms have been devised over the lastseveral decades. The mechanisms employ a tiltable track section mountedon a transverse pivot axis. Such a track section is normally cooperativewith an upper track along which the full mold rides on a carrier or car,and cooperative with a lower track along which the empty mold car rides.Due to the economic necessity of automating foundry equipment as much aspossible, even in small and medium size foundries, emphasis has beenplaced on efforts to effect an automatic dumping mechanism that wouldreceive the car from the upper track, tilt it in one direction to dumpit, then tilt it in the opposite direction to send the car back alongthe lower track, and finally tilt back to the initial position to latchto the upper track. One type of mechanism for doing this is illustratedin US. Patent No. 2,830,716. While automating this series of operationswould seem relatively simple, and while the apparatus disclosed in theabove identified patent does operate, in every day foundry practice,continued dependable performance of such automated 3,448,873 PatentedJune 10, 1969 "ice equipment does not always occur due to particularproblems occurring in foundries. Particularly, the electrical limitswitches, solenoid valve actuators, and signaling devices employed tocontrol the power actuation of the dumping mechanism sooner or laterbecome inoperative or undependable because of dust, sand, and othercontaminants penetrating the electrical system.

One type of mold dumping device employs a pressure actuated piston inwhich a single pressure operated cylinder is employed to actuate therotational movement of the tiltable track system. In this system, alatch mechanism must be employed to maintain the tiltable track in analigned relationship with the upper track. With continued and frequentuse of the device, there results breaking or wear of the latch due tothe banging of the same against the cooperating locking portion of theupper track.

Some of the mold dumping devices use the weight of the mold to assist inthe dumping operation. While this system is very helpful in the dumpingoperation, the overall system is more expensive to construct since thetrack must be high enough to dump the contents of the car into acontainer and conveyor. It is generally undesirable to dig a pit for theconveyor since the presence of ground water tends to contaminate themolding sand.

Thus, it is desirable to have a tiltable track section wherein the trackrotates substantially about an end so that the upper track can be spacedreasonably close to the floor without having to dig a pit for theconveyor.

Granath 2,681,738 discloses a molding pallet dumping device in which apair of fluid cylinders operate the dumping and transferring of the moldcars. This device, however, requires special separate linkagestructures, a special expensive double tilt track assembly, and specialarrangement of the fluid cylinders with this complex mechanism. Theentire assembly is complex and costly.

I have now discovered a uniquely simplified, highly dependable molddumping system whereby a tiltable track is power rotated substantiallyabout one of its ends using a specially arranged and oriented pair offluid cylinders capable of actuating the tiltable track without anyextraneous complex, expensive mechanical linkages or double trackapparatus.

By various aspects of this invention one or more of the following, orother objects, can be obtained.

It is an object of this invention to provide an improved system fordumping mold cars wherein a high dump is employed.

It is a further object of this invention to provide a fully power-drivensystem for dumping mold cars and the like wherein mechanical latches andlinkages are avoided.

It is still a further object of this invention to provide a pneumaticsystem for dumping mold cars wherein a single mechanical arrangement isemployed for rotating the tilting track.

It is still a further object of this invention to provide a controlsystem for the operation of a fluid operated dumping system.

Other aspects, objects, and the several advantages of this invention areapparent to one skilled in the art from a study of this disclosure, thedrawings, and the appended claims.

According to the invention, there is provided a mold dumping assemblyincluding a stationary feeding track, a dumping track rotatable about ahorizontal axis at one end thereof and a stationary return track, andpower means to rotate the dumping track from a first position alignedwith the feeding track to a second position in a dumping position, andto a third position wherein the dumping track is aligned with the returntrack. The power means employed in this invention comprises a firstfluid pressure operated cylinder operably connected to the dumping trackmeans and a second fluid pressure cylinder 3 rigidly attached to thefirst pressure cylinder and rotatably attached to a fixed point. Thefirst and second fluid pressure cylinders are preferably positionedadjacent each other in side by side relationship.

The invention will now be described with reference to the accompanyingdrawings in which:

FIG. 1 is a side elevational view of a dumping track assembly accordingto the invention wherein the tiltable dumping track is aligned with thestationary feeding track;

FIG. 2 is a side elevational view of the assembly of FIG. 1 wherein thetiltable dumping track is in the dumping position;

FIG. 3 is a side elevational view of the assembly shown in FIGS. 1 and 2wherein the tiltable dumping track is aligned with the return track;

FIG. 4 is an end elevational view of the assembly shown in FIGS. 1, 2and 3 wherein the tiltable dumping track is aligned with the feed track;and

FIG. 5 is a schematic diagram of the pneumatic control system employedin the system shown in FIGS. 1 through 4.

Referring now to the drawings, a stationary horizontal feed track 2 isaligned with horizontal dumping track 4 which is rotatable substantiallyaround one of the ends by pivoting on shaft 6. The tiltable track 4 isrotatable such that it can be aligned with stationary return track 8 (asshown in FIG. 3).

The stationary tracks 2 and 8 are supported by vertical support beams 10and 12 which are connected by cross members 14, 16, 18, and 20, and alsoby a longitudinal support beam 44.

The tiltable track has an end stop member 24 adapted to be abutted by awheel of a car positioned on the tiltable track. One end of the tiltabletrack 4 is supported by vertical member 22 and rotatable shaft 6. Spacedfrom this rotatable shaft 6 is a flange 26 through which the tiltabletrack 4 is attached to the power means. The flange 26 is rotatablyattached through pin 28 to the end of a piston rod 30. A fluid operatedcylinder 32 actuates the movement of piston rod 30. A second fluidoperated cylinder 36 is attached through bolts 34 to fluid operatedcylinder 32 in side by side relationship. Fluid cylinder 36 has a pistonrod 38 which is rotatably attached to beam 45 through a flange 40 and arod 42.

The downward rotation of track 4 is limited by stop 58 which is fastenedto beam 44 (FIGS. 3 and 4).

A mold car 48 having wheels 50 and mold 49 is adapted to ride on thetracks 4 and 8.

A switch 52 is provided on the end of tiltable track 4 to initiate themovement of the track to the dumping position. This switch 52 is trippedby a loaded car as it reaches the end of the track. A second switch 54is provided on support member 22 to initiate the movement of thetiltable,track 4 to the return position. This switch is triggored by theend of the tiltable track 4 supporting member as it rotates to theposition shown in FIG. 2. A third switch 56 is positioned on the top ofstop 58. This switch 56 is tripped by tiltable track 4 as it reaches thereturn position. This switch initiates the return movement of the track4 to the horizontal position. The switches can be levers with rollers orother similar cam followers on the ends thereof.

In operation, a mold car 48 with a mold 49 is advanced along track 2until it reaches track 4 which is normally in the horizontal position inFIG. 1. When the car is positioned on track 4, switch 52 is tripped andthe control system begins to function. In this first position, thepiston rod 38 will be completely extended and the piston rod 30 will becompletely retracted. The tripping of the switch 52 by the car actuatesa pilot valve which allows fluid pressure to flow into cylinder 32 tocause piston rod 30 to extend to the position shown in FIG. 2 to tiltthe track 4 so that the mold 49 slides from the car into a receivingcontainer 46. The sand and the casting in container 46 will be conveyedto a separating area for recovery of the sand for reuse and recovery ofthe cast product.

When the track 4 reaches its tilted position in the counterclockwisedirection as shown in FIG. 2, switch 54 is actuated to exhaust the fluidfrom cylinders 32 and 36 thereby causing track 4- to tilt to itslowermost position as shown in FIG. 3. In this position, piston rods 38and 30 will be completely retracted. As the track reaches this lowermostposition, the mold car will roll down the track and onto the returntrack 8. When the track reaches the lowermost position, switch 56 willbe tripped which after a short delay will cause the pressure to besupplied to cylinder 36 to extend piston rod 38. This extension ofpiston rod 38 will return the tiltable track 4 to the horizontalposition shown in FIG. 1.

With the use of the invention, especially the embodiment shown in FIGS.1 through 5, a high dump can be employed with a relatively simplemechanical arrangement. The whole system employs only a few movingparts. For example, the Whole system employs only three points ofrotation and no other mechanical linkages. Further, the side by siderelationship of the piston cylinders permits a high dump of the tiltingtrack and a relatively low positioning of the feed track 2 and returntrack 8. For example, with the use of the system shown in the drawings,the feed track can be about three feet above the floor, the return track8 can be about 2%. feet above the floor and the container 46 can haveits top portion only 2% feet above the floor.

Referring now specifically to FIG. 5, the control system is operated bythe fluid pressure source such as air which is passed through line 60,through branch line 62, line 64, valve 66, lines 68 or 70 to cylinder32. Also, the fluid pressure is passed to line 76, valve 86, lines 78 or82 to shoulder 34. Lines 68, 70, 78 and 82 all have speed controlrestrictions 67, 69, and 84 respectively in the lines. Valve 66 is aspring biased, pilot operated valve. Valve 86 is a pilot operated valve.

Valve 66 is actuated by fluid pressure which passes through line 72,valve 53, line 73, valve 74 and line 75. Valve 74 is a detent pilotoperated valve which is actuated when fluid pressure passes throughvalve 55 or valve 98. When the valve 74 is pushed to the left, any airpressure in line 73 will be blocked by a plug at 77. When valve 55 isopened, the fluid pressure will pass through line 88, line 94-, throughtime delay 90, line 92 to shift valve 74 to the left. The air pressurewill also pass through line 96 to pilot valve 86 to shift the valve 86to the right.

When valve 98 is opened, the air pressure will pass through line 100,and through line 102 to the left side of pilot valve 74 to thereby shiftthe valve to the right. The air pressure will also pass through line104, through time delay 106 to the right side of pilot valve 86 to shiftthat valve to the left.

In operation, valves 53, 55 and 98 are normally closed. In this normalcondition, the tiltable track will be horizontal. Valve 74 will bepositioned to the right as shown in the drawings; valve 66 will bepositioned to the left; and valve 86 will be positioned to the left.When a car on a track trips switch 52, the valve 53 will open to allowair pressure to pass through line 73, valve 74, line 75, to pilot valve66 to shift the valve 66 to the right. The air pressure will then passthrough speed control restriction 69, line 70, to the lower end ofcylinder 32 to cause the pitson rod associated therewith to extend. Thisextension will rotate the tiltable track to the dumping position (FIG.2).

As the track reaches the position shown in FIG. 2, the track will tripswitch 54 to open valve 55. The air pressure will pass through line 88,valve 55, line 94, through time delay to line 92 and the right side ofpilot valve 74. This will cause the valve 74 to shift to the left,thereby venting the fluid in line 75. At this time, valve 53 will stillbe open but the air pressure will be blocked by plug 77.

5 The release of air in line 75 causes the valve 66 to shift to the leftto permit the air pressure to pass through line 68 to the upper portionof cylinder 32, thereby retracting the cylinder. At the same time, theair pressure will be exhausted from the lower end of cylinder 32 throughline 70 and speed control restriction 69.

Simultaneously, the air pressure will pass through line 96 to pilot onthe left side of valve 86. This pressure will shift the valve 86 to theright thereby permitting fluid pressure to pass through speed controlrestriction 84, line 82 to the lower end of cylinder 34. This pressurewill cause the piston rod of cylinder 34 to retract. At this same time,the air pressure in the upper end of cylinder 32 will be exhaustedthrough line 78 and speed control restriction 80.

This retraction of the piston rods of cylinders 32 and 34 will cause thetiltable track to rotate to the return position (FIG. 3). In this returnposition, the track will actuate switch 56 to open valve 98. At thistime, valves 53- and 55 will close. The air pressure then passes throughline 100, valve 98, line 102 to the left side of pilot valve 74. Thispressure on the left side of pilot valve 74 causes the valve to shift tothe right. However, since no pressure is passing through line 53, therewill be no change in valve 66. The air pressure also passes through line104 through time delay 106 to the right side of pilot valve 86 to shiftthe core of valve 86 to the left after a suitable time delay. A timedelay 90 also limits the rate of the exhausting of fluid from lines 92and 96. The air pressure will then pass through line 76, line 78 to theupper end of cylinder 34 to cause the piston rod of that cylinder to beextended. This will raise the tiltable track back to the horizontalposition. Therefore, after a short delay, the track will be raised fromthe return poistion to the horizontal position. The delay is provided topermit the car on the tiltable track to roll onto the return track.

The invention has been described with reference to an automaticallycontrolled system, it is within the scope of the invention to provide amanually operated switch in place of switch 52. In this manner, theoperation can be made semi-automatic with the operation of valve 53 tostart the dumping operation being done manually.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure and the drawings without departing from thespirit of the invention.

I claim:

1. In a low profile mold dumping assembly including a stationary feedingtrack, a dumping track rotatable about a horizontal axis at one endthereof, a stationary return track, and a power means to rotate saiddumping track from a first position aligned with said feeding track to asecond position in a dumping position, and to a third position whereinsaid dumping track is aligned with said return track, the improvementwhich comprises a power apparatus formed of a first fluid pressureoperated cylinder operably connected to said dumping track means, asecond fluid pressure cylinder directly attached to said first fluidpressure cylinder, and rotatably attached to a fixed mount.

2. A mold dumping system according to claim 1 wherein said first andsecond cylinders are so arranged and powered that a piston rod of saidfirst fluid pressure cylinder is retracted when said dumping track is insaid first position, is extended when said dumping track is in saidsecond position, and is retracted when said dumping track is in saidthird position, a piston rod of said second fluid pressure cylinder isextended when said dumping track is in said first position, is extendedwhen said dumping track is in said second position, and is retractedwhen said dumping track is in said third position.

3. A mold dumping system according to claim 2 including a first switchmeans positioned to be activated by a car at the end of said dumpingtrack, and operably associated with said first fluid pressure operatedcylinder said first switch means is activated by a car, a second switchmeans positioned for actuation by said dumping track actuates said firstand second cylinder to retract said piston rods, and third switch meansfor actuating said second cylinder to extend said piston rod associatedtherewith when said dumping track is in said third position.

4. A mold dumping assembly according to claim 3 wherein there is furtherprovided a timing means associated with said third switch means to delaythe extending of said piston rod associated with said second cylinder toraise said dumping track when in said third position to permit said carto roll onto said return track.

5. A mold dumping assembly according to claim 1 wherein said first andsecond pressure operated cylinders are attached to each other in side byside relationship such that the direction of movement of piston rodsassociated with each of said first and second pressure operatedcylinders is parallel, and the position of said piston rods areoverlapping when both are retracted.

6. A mold dumping assembly according to claim 1 wherein said first andsecond cylinders are actuated by first and second valve meansrespectively;

a first switch means is operably associated with said first valve meansand is located relative to said dumping track to be actuated by a carthereon, to thereby actuate said first valve means to extend a pistonrod associated with said first cylinder when a car is received on saiddumping track,

a second switch means is operably associated with said first and secondvalve means and located relative to said dumping track to actuate saidfirst and second valve means to cause retraction of piston rodsassociated with said first and second cylinders when said dumping trackreaches said second position,

a third switch means is operably associated with said dumping track andsaid second valve means to actuate said second valve means to extendsaid piston rod associated with said second cylinder when said dumpingtrack reaches said third position.

7. A mold dumping assembly according to claim 6 wherein time delay meansare operably associated with said third switch means to delay actuationof said second valve means for a predetermined time after said thirdswitch is activated to permit a car on said dumping track to roll fromsaid dumping track to said return track.

8. A mold dumping assembly according to claim 6 wherein said first valvemeans is a spring biased pilot operated valve,

a first conduit means is provided for supplying fluid pressure to thepilot end of said first valve means, said first switch means controls afirst cam valve in said first conduit means,

said first cam valve being adapted to connect said pilot end of saidfirst valve means with a fluid pressure source or to vent pressure fromsaid pilot end of said first valve.

9. A mold dumping assembly according to claim 8 wherein said secondvalve is a pilot operated valve,

second and third conduit means are provided to supply fluid pressure toeither end of said second valve for actuating said second vailve,

said second switch means operates a second cam valve in said secondconduit means, said second cam valve being adapted to supply fiuidpressure or to exhaust fluid pressure from one end of said second valvemeans,

said third switch means operates a third cam valve means in said thirdconduit means,

said third valve being adapted to supply fluid pressure to, or exhaustfluid pressure from the other end of said second valve means.

10. A mold dumping assembly according to claim 9 wherein a third pilotoperated valve is provided in said to cause it to be actuated to extendsaid piston rod when first conduit means between said first cam valveand said 7 a I first valve means to exhaust fluid pressure in said pilotend of said first valve means when said second switch means is actuated,

said second conduit means communicates with one end of said third pilotoperated valve such that said second calm valve controls the flow offluid pressure to said one end of said third pilot valve,

said third conduit means communicates with another end of said thirdpilot operated valve such that said third cam valve controls the flow offluid pressure to said other end of said third pilot operated valve toreturn said third pilot operated valve to the condition whereby fluidpressure can be supplied to said pilot end of said first valve means.

References Cited UNITED STATES PATENTS 6/1954 Granath 214-4622 9/1960Murphy 2l4--46.22

ROBERT G. SHERIDAN, Primary Examiner.

